Clamp for perforated sheet material



March 11, 1941.

E. K. DEGENER 2,234,938 CLAMP FOR PERFORATED SHEET MATERIAL v Filed sept. 16. 1940 M@ ssi;

INVENTOR.

Edward K QETLET ATTORNEYS.

Patented Mar. 11, 1941 UNITED STATES PATENT `or-'FlcEf 2,234,938 CLAMP FOB PERFOBATED SHEET MATERIAL Edward K. Degenen', Los Angeles, Calif. Application September 16, 1940, Serial No. 357,037

12 Claims.

The present'invention relates to fastening devices for use in assembling perforated sheet material preparatory to riveting or otherwise permanently securing the sheets together.

The primary object of the invention is to provide a clamp for use in assembling aeroplane wings and similar fabricated sheet metal structures to facilitate riveting the sheets together.

A further object of the invention is to provide a sheet clamp which is small, durable and compact, and which may be operated by one hand for quickly clamping the sheets together without requiring the use of separatetools for op erating the clamp. v

A further object is to provide a sheet clamp of this character which is readily adjustable for clamping together sheets of diierent thickness. and which will yalso assure perfect alignment oi the rivet holes.

A still further object is to provide a sheet clamp ci' this character which may be produced at a relatively low cost, and in which a cam action is employed for operation of the clamp.

@ther objects and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawing and in which drawing- Fig. i is .a View part in section and part in eleration of the improved clamp shown in open position, and showing the clamp in position as hrst applied to the sheets to be clamped together.

rig. 2 is a view part in side elevation and part in section oi the clamp in the second position as applied 'to the sheets.

lille. 3 is a side view showing the clamp in closed operative position upon the sheets.

ills. i is a side view at a right angle to the showine in Fig. 3.

ille. t is a top plan View of the position.

lullig.. 6 is a bottom plan view of the clamp in open position.

lilas. 7 and 8 are enlarged transverse sections on the respective lines in Fig. l.

ille. 9 is a longtudinal section thru clamp in open the clamp body member.

lilla. itl is an enlarged section thru the com` formed with a segmental cut out I5 which extends to the upper end of the body member and forms a slide surface for a purpose later described. The chord of the segmental cut out I5 intersects the bore I4 of the body member yI2 5 l Threaded upon the lower end of the body member I 2 is an abutment member Il in the form of a round nut providing a dat under surface flush with the lower end of the body member I2. This abutment member Il after being threaded on the body member is secured as by welding or other suitable means. Slidable on the upper portion of the body member l2 is a washer member I8 formed with a fiat depending lug I9 which extends at a right angle to the plane of the washer and has sliding movement along the slide surface I5 whereby the washer member is slidable and non-rotatable on the body member. 'I'he lug or plate I9 is provided with a round opening having its axis in alignment with the diametrically formed guide way I6.

Threaded on the body member I2, above the ilxed abutment Il is an adjusting nut 2l forming a seat for the lower end of a compression spring 22 having its upper end seating against the under side of the washer member IB.

Slidable and independently movable in the circular bore M are two plunger rods 23 and 24 forming pilot and clamping rods respectively. These plunger rods 23 and 24 are of semi-circular cross section and form a circle oi" a diameter' equal to that oi' the bore ill. Projecting laterally from the upper endA of the pilot rod i3, and from the circular i'ace oi the rod, is a coupling head it which extends into the opening lo in the iupr it lor connecting the pilot rod to the washermember il. Thus the pilot rod 23 is connected for movement with the washer member i8. 'The lower end of the pilot rod 23 is beveled or tapered on its circular face as at 26 and normally projects lor a short distance beyond the bottom face of the abutment member Il. Y

The clamping rod 24 is of greater length than that of the pilot rod 23 and is formed at its lower or outer end with an arcuate bend or offset 28 which extends outward from the circular face of the rod and terminates at its' lower end in the plane of the flat inner face of the rod. The upper end of the clamping rod 24 extends thru the opening in the washer member I8 and is formed with a T-head providing a cross pin 28 iittlng in the guideway I8. The ends of the cross pin III project beyond the body member I2. Pivoted upon the cross pin 8l isan opera lever l2 embodying a U-shaped cam member formed with a pair of parallel spaced apart eccentric cam plates 23 which straddle the upper end of the body member I2 above the washer lmember I8. A lever arm 34 extends from the connected edges of the camplates for swinging the cam member about its pivot on the pin Il. The cam faces or edges 85 of the eccentric cam plates 23 are arranged to bear upon the upper face of the washer member I8 whereby upon pivoting of the operating or clamping lever, the

plunger rods 2l and 24 will have relative movement imparted thereto.

In use of the device for clamping together perforated sheets, the numerals 40 and 42 may respectively designate inner and outer sheets which are provided with perforations 4I that are to receive rivets or other fastening elements for securing the sheets together. The circle formed by the semi-circular shaped plunger rods 28 and 24 has a diameter substantially equal to the diameter of the perforations 43. With the operating lever or cam l32 in the open position as in Figure 1, the pilot rod 22 is in its retracted position due to the action of the spring 22 which is shown in its normal extended condition; while the end of the clamp rod 24 extends for somewhat beyond the end of the pilot rod. In this position, the arcuate ,bend or onset 28 may be inserted thru the perforations 43 so as to assume the position shown in Figure 1 `and then the abutment member I1 moved against the Y outer sheet 42 as in Figure 2 where upon the beveled end of the pilot rod 23 will extend 'partially into the aligned perforations.

The operating lever 32 is now swung for clamping the sheets together thru the following action. When the lever 22 is in the dotted position shown in Figure 2, the action of the cam plates 23 bearing upon the washer member vIB will have caused the clamping rod 24 to be moved upward in the body member I2 and the arcuate bend 28 into engagement with the inner side of the inner sheet 40. Continued swinging of the operating lever 32 causes the cam plates 33 to impart a downward movement on the washer member I8 and compresses the spring 22. This downward movement of the washer member I 8 projects the pilot rod 23 so that the end of the pilot rod aligns with the end of the clamping rod'24 as in Figure 3. When the lever arm 34 comes to rest beside the spring 22 as in Figure 4, the sheets 40 and 42 will be rmly held together between the abutment member l1 and the arcuate ben`d 28 and may be released by the operator.

When the clamp is in a closed position as in Figures 3 and 4, it will be seen that the spring 22 acting upon the washer member I1 urges the arcuate bend 28 against the inner face of the inner sheet 40, and thru engagement with the adjusting nut 2l urges the abutment member I1 against the outer face of the outer sheet 42 thus firmly clamping the sheets together. Upon opening the operating lever 32, the spring 22 will expand to retract the pilot rod 23 and permit the arcuate bend 28 on the clamping rod 24 to be withdrawn from the sheets.

The nut 2| is for adjusting the clamp for different thickness of metal sheets so that the lwasher member slidable on :the body member, a

desired clamping pressure may be had on the sheets. When the clamp is used for clamping sheets which may be thinner than that illustrated in the drawing, the nut 2i is threaded upward on the screw threads Il so that a great. er compression on the spring 22 is obtained when the clamp is closed.

The clamps are constructed as complete units and different size bores will be drilled in the body member I2 to accommodate diilerent size plunger rods in accordance with the size of the perforations in the sheets to be clamped together.

Changes in' detail may be made to the form of invention herein shown and described without departing from the spirit of the invention or the scope of the following claims.

I claim:

1. A sheet clamp for holding together superposed sheets of perforated sheet material, comprising a body member having an abutment at 20 one end, a pair of plunger rods independently and reciprocally movable in the body member and projecting thru said abutment for insertion into perforations in the sheets, a lateral projection on one of the plunger rods, and cam actu- 25 ated spring means associated with the body member and plunger rods for clamping the sheets between said abutment and the lateral projection.

l 2. A device for clamping together superposed 30 perforated sheets, comprising a body member, a pilot rod slidable in the body member and having a lateral extension, a coil spring normally retracting the pilot rod, and a cam member connected with a clamping rod and acting upon the coil spring whereby the clamping rod will be retracted and the pilot rod extended relative to the body member.

3. A device for clamping together superposed perforated sheets, comprising a body member, a pilot rod slidable in the body member and having a lateral extension, a washer member slidable on the body member and connected to the pilot rod, a compression spring acting between the body member and washer member, and a "cam member pivoted on a clamping rod and acting upon the washer member for compressing the spring and extending the pilot rod subsequent to retracting of the clamping rod whereby the sheets are clamped between an end of the body member and said lateral extension.

4. A sheet clamp for superposed perforated sheets, comprising a body member having a bore, an abutment at one end of the body member, a

pilot rod slidable in the bore and connected to the washer member, a clamping rod slidable in the bore for cooperating with the pilot rod and having an arcuate oilset, a coil spring acting between the washer 'member and said abutment and an operating lever including a cam portion pivoted to the clamping rod and acting upon the washer member for compressing the spring and clamping said sheets between the abutment and said arcuate offset.

5. A sheet clamp of the character described, comprising a cylindrical body member having an axial bore, an abutment at the lower end of the body member, a washer member slidable on the body member, a coil spring encircling the body member between the washer member and the abutment, a pilot rod slidable in said bore and connected at its upper end to the washer member, a clamping rod slidable in said bore and hav.. ing an arcuate oiIset at its lower end, a cross with.

pin on the upper end ofthe clamping rod above the washer member, and an eccentric cam pivoted on the cross pin and acting on the washer member for compressing said coil spring.

6. A sheet clamp of the character described, including a body member, a companion pair of sheet engaging plunger rods reciprocably movable in the body member, a compression spring active between the body member and one plunger rod, and a cam member connected with the other plunger rod for compressing said spring whereby the body member and one of the plunger rods are moved into sheet clamping relation.

7.. A sheet clamp of the character described,

`including a body member, a companion pair of sheet engaging plunger rods reciprocably movable in the body member, a compression spring active between .the body member and one plunger rod, means for adjusting lthe compression on the coil spring, and a cam plate pivoted on one of the plunger rods for imparting reciprocatory movement thereto and also compressing said coil spring for extending the plunger rod associated thered. A sheet clamp for superposed perforated sheets, comprising a cylindrical body member having an axial bore, a. companion pair of pilot and clamping rods slidable in Ithe bore, an abutment on one end of the body member, a washer member slidable on the body member, means connecting the pilot rod to the washer member, a. coll spring acting between the body and washer members, a sheet engaging extension on the clamping rod, and a clamp plate pivotally connected to the clamping rod and having a cam action upon Ithe Washer member for compressing the coil spring. l

9. A sheet clamp for superposed perforated sheets, comprising a cylindrical body member having a threaded lower end portion, an abutment xed on the lower end of the body member, a nut threaded on the body'member above the abutment, a washer member slidable on .the body member, a coil spring between the washer member and said nut, coacting pilot and clamping rods reciprocable in the body member, means connecting the pilot rod to the washer member, and a cam lever pivoted on the clamping rod and acting upon the washer member for compressing said coil spring. y

v 10. A sheet clamp comprising a cylindrical body member having an axial bore and an externally threaded lower end portion, a longitudinal slot in the upper end portion of the body member, an abutment on the lower end of the body member, a nutthreaded on the body member., a washer slidable on the body member, a coil spring acting between the washer member and .the abutment, a coacting pair of pilot and clamping rods fitting in said bore, means connecting the upper end of the pilot rod to the washer member, an arcuate offset on the lower end of the clamping rod, a cross pin on the upper end of the clamping rod and guided in said slot, and a U-shaped cam member straddling .the body member and having cam plates pvoted on said cross pin.

11. A sheet clamp comprising a body member having a circular bore, a coacting pair of pilot and clamping rds of semi-circular cross section fitting in said bore,y an arcuate oiset on the outer end of the clampingrod, a spring active between the body member and pilot rod, and cam means active between .the spring and clamping rod for extending the pilot rod subsequent toA retracting of .the clampingrod.

12. A sheet clamp comprising a body member, a body member, pilot and clamping rods independently sldable in the body member, and a cam actuated tensioning means active between the body member and rods for clamping superposed sheets between the body member and the clamping rod.

EDWARD K. DEGENER. 

